Light assembly

ABSTRACT

A lighting assembly ( 10 ) which extends through the thickness of a wall ( 14 ) having a first side ( 16 ) and a second side ( 20 ) is described. The lighting assembly ( 10 ) comprises at least one light source ( 46 ) to illuminate an area on the first side ( 16 ) of said wall ( 14 ) and means being included to enable replacement of said light source from the second side ( 20 ) of said wall ( 14 ) wherein said means includes at least one duct ( 30 ) extending at least part of the way from the first side ( 16 ) of the wall ( 14 ) to the second side ( 20 ) of the wall ( 14 ); light source carrier means ( 50 ) on which said light source is mounted, said light source carrier means ( 50 ) and said light source ( 46 ) being movable through said at least one duct ( 30 ) from said second side ( 20 ) to said first side ( 16 ); moving means ( 80 ) to move said light source ( 46 ) and said carrier means ( 50 ) through said at least one duct ( 30 ); and, power supply means to said light source ( 46 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lighting assembly which extendsthrough a wall particularly, though not exclusively, for illuminating anun-manned area.

2. Description of the Prior Art

In un-manned areas such as, for example, so-called “caves” whereradioactive materials are being remotely handled, it is necessary toprovide a high level of illumination. Two principal types of lightingsystems are used for lighting nuclear processing areas. The first is bysealed lighting units hung at stations within the cave and which arecapable of being remotely disconnected and removed from the facility formaintenance as indicated schematically in FIG. 12. The second type areunits inserted through the wall of the facility and have the lightingmeans emerging into an enclosed section with a window on the un-mannedside to allow the light to shine on the area or objects to be viewed andas indicated schematically in FIG. 13.

The first type has the disadvantage that that the unit has to be removedfrom the radioactive area using remote handling equipment, potentiallytying up scarce resources such as the in-cell crane and operators timefor example. The removed unit then has to be transferred to amaintenance area for decontamination before it can be repaired, then tobe reinstalled in its position within the cave using the crane again.

The second type of lighting system has an advantage over the first typein that the maintainable parts are located outside of the caveenvironment and there is no requirement for the use of cranes ormanipulators within the cave so that processing is not interrupted noris there any decontamination of the lighting device required which savescost due to there being no waste arisings to be further processed.However, current designs of through-wall lighting systems of the secondtype have their own particular disadvantages which relate mainly toweight and safety aspects. Current designs of throughwall lightsnecessitate the removal of a large shielding wall plug comprising mainlyconcrete grout and which weighs in the region of 700 kgs. The wall plugis unwieldy and awkward to extract as the wall has a thickness of some1-1.5 m and requires special equipment by way of a handling deviceweighing about 1000 kgs and specially trained personnel using aprocedure which ensures that no radiation hazard is produced.

When nuclear processing facilities are built, many additional lightingunits are initially installed to provide for redundancy and the factthat new light tubes will all be installed simultaneously and hencelikely to fail at about the same time.

Currently, about 20 man hours are required to change a light tube inknown through-wall lighting designs.

A further disadvantage of current designs is that although they have aclosed cover into which the light tube emerges in use, this cover issometimes broken accidentally by a manipulator or in-cell crane forexample. Thus, when the light tube is to be replaced, it is necessaryfor a much more rigorous and hence time consuming and expensiveprocedure due to the safe-side of the wall being open to contaminationby radioactive dust and debris for example.

SUMMARY OF THE PRESENT INVENTION

It is an object of the present invention to provide a through-walllighting unit which allows easier, more economic and safer maintenanceand replacement of failed lights than existing systems.

According to the present invention, there is provided a lightingassembly which extends through the thickness of a wall having a firstside and a second side, the assembly having at least one light source toilluminate an area on the first side of said wall and means beingincluded to enable replacement of said light source from the second sideof said wall wherein said means includes at least one duct extending atleast part of the way from the first side of the wall to the second sideof the wall; light source carrier means on which said light source ismounted, said light source carrier means and said light source beingmovable through said at least one duct from said second side to saidfirst side; moving means to move said light source and said carriermeans through said at least one duct; and, power supply means to saidlight source.

In the present invention, the light source may be any required lightsource for the purpose intended. Examples of light sources may includegenerally rounded light bulbs, quartz-halogen bulbs, light tubes such ashigh-intensity sodium tubes or any other desired light source. The mainrequirement is that the shape of the passage through the duct and thecarrier means may be adapted to the type and shape of light source inquestion.

Furthermore, the method and apparatus of the present invention fordeploying a light source may also be used to locate and deploy otherlighting and surveillance means such as cameras, fibre optics forlighting or lasers or cameras or video recording apparatus for example.Therefore, any reference to ‘light sources’ should be taken to includesuch alternative devices and apparatus.

The lighting assembly according to the present invention may alsoinclude location means at the first side to locate the light source in adesired position.

The number of ducts within the lighting assembly may be partiallydependent upon the shape of the light source itself. In the case wherethe light source is of generally rounded form, there may be a pluralityof ducts. Where the shape of the light source is of generally elongatetubular form, there may be only one duct.

The lighting assembly according to the present invention may be intendedfor a nuclear processing facility. However, the lighting assembly of thepresent invention may equally well be employed in other specialenvironments such as clean rooms, sterile areas and explosiveatmospheres for example.

The component parts of the lighting assembly of the present inventionmay be contained within a container housing which is adapted to fitclosely within a shaped aperture in the wall through which the assemblyis to extend or, in the case of new facilities being built, the shape ofthe aperture through the wall may be such as to conform to the shape ofthe lighting assembly housing. The wall aperture may alternatively havea liner therein adapted to seal against said container housing forincreased confidence against leakage of contaminants from the first sideto the second side.

The end of the container housing adjacent the first side of the wall mayinclude reflector means of a desired shape to enable said light sourceto illuminate the area on the first side in a particular manner. Theshape of the reflector means required will be known to those peopleskilled in the lighting art and will not be elaborated on further. Thelocation means may locate the light source in a position consistent withthe requirements of the reflector means to permit efficientillumination. The location means may contain features whichautomatically locate the light source in the desired position on beingmoved to the first side of the duct.

Since there is no need to remove the container housing from the wallduring replacement of the light source in the lighting assemblyaccording to the present invention, the container housing may be filledin the free volume about the duct by, for example, concrete grout in thesame manner as existing lighting systems but which do need to be removedduring light source changes. Thus, in the present invention, materials,such as the grout for example, which are fully characterised andquantified may be used so that confidence in the shielding efficiency ofthe lighting assembly of the present invention is as high as with priorart systems.

The duct, in the case of a lighting assembly intended for a nuclearprocessing facility may be non-linear so as to preclude a so-calleddirect shine path being available from the first side to the secondside. In one embodiment of a lighting assembly according to the presentinvention, the shape of the duct from a side elevation may be of agenerally sinusoidal-type form but its precise shape will be dependentupon the requirements for the prevention of the passage of primarily yrays by internal reflection in the duct from the first side to thesecond side. The cross-sectional shape of the duct may be generallyrectangular.

In a second embodiment of the present invention where there are aplurality of ducts, these may be “twisted together”, each duct beinggenerally in the form of a helix extending from the second to the firstside; the cross-sectional shape of each duct being generally circular.In this second embodiment, the shape of the individual light sources maybe generally rounded.

The form and type of the light source carrier means may be largelydetermined by the shape and positional requirements of the light sourceand consequently by the cross-sectional shape of the duct. In a firstembodiment of the present invention where the light source is ofelongate tubular form which should desirably be positioned in ahorizontal attitude and specific location relative to a reflector meansto achieve a downwardly illumination direction, the carrier means maycomprise a trolley or bogey on which the light source may be mounted ata front end thereof relative to the first side. The trolley may havemeans to maintain it in a desired spatial orientation and positionwithin the duct. Such means may comprise jockey wheels, for example,running on internal horizontal and/or vertical surfaces of the duct.

In a second embodiment of the present invention, the carrier means maycomprise generally rounded light source holders able to be slid orpushed through the duct by the moving means.

Where the duct is non-linear, flexible placement and retractor movingmeans are required to enable the light source to be passed through theduct and be placed at its desired location at the first side and to beretracted therefrom to enable replacement of the light source. In afirst embodiment where the duct is of generally rectangular internalcross-sectional shape, the flexible placement and retractor moving meansmay comprise the type of plastics material chain-track conveyor havinghollow box-like segments in linear array and pivoted to each other andcommonly used on machine tools and conveying systems for example forgrouping together and protecting moveable power supply leads or cablesand preventing snagging and kinking thereof; such chain-track beingflexible in a single plane. Power supply cables to the light source maybe run through the flexible moving means and in which they are protectedand prevented from snagging during movement of the light source andcarrier means. The moving means may alternatively comprise a flexible,flat metal strip which is able to conform to the internal curves of theduct.

In a second embodiment of the present invention, where the light sourcesare of generally rounded form, the moving means may comprise a flexibleconduit able to adapt to the curvature of the duct. Similarly, asdescribed above, the power supply cables to the light source may be runthrough the flexible conduit.

In the first and second embodiments of moving means described above, theinternal duct walls provide adequate support to the moving means whilstthe light source and carrier is being pushed through the duct.

Other embodiments of moving means may comprise rotatable pulley wheelsin fixed positions at least adjacent the first and second sides of theduct having an endless cable therearound and the carrier means in theendless cable loop.

Ducts which are of substantially linear form may employ rigid movingmeans to push the light source from one side to the other.

Power source supplies to the lighting assembly of the present inventionmay be conventional and will not be elaborated upon further.

A separate closed translucent cover on the wall on the first side may beprovided if desired but is not necessary as is the case with prior artdesigns.

At the second side of the lighting assembly, remote from the hazardousarea, the duct orifice may be provided with a closure having a seal,thus sealing the duct second side if any damage should occur to theglass of the lighting assembly at the first side.

The container housing at the second side of the wall may also beprovided with a closure cover having a seal therearound to provide afurther safety margin in the event of damage to the assembly on thefirst side.

Fluid coolant supplies may be provided in the lighting assembly of thepresent invention to enable cooling of the light source to prolong thelife thereof. Such coolant supplies may be provided through flexibleconduits which run through the moving means with the power supply cablesor may be provided through conduits which are fixed within the containerhousing. Since the interior of the duct and the container housing areboth sealed off from the environments on both the first and second sidesof the wall, it may only be necessary to provide a fluid inlet to thecontainer housing in the region of the light source and a fluid outletat another position or positions. The fluid coolant system may be aclosed circuit with pumping means and heat exchanging means for example.

In order that the present invention may be more fully understood,examples of the present invention will now be described by way ofillustration only with reference to the accompanying drawings, of which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section in elevation of a first embodiment of alighting assembly according to the present invention situated in a wall;

FIG. 2 shows a view of the first side in the direction of the arrow A ofFIG. 1;

FIG. 3 shows a view of the second side in the direction of the arrow Bof FIG. 1;

FIGS. 4A and 4B show a plan and side elevation of carrier means for theembodiment of FIG. 1;

FIG. 5 shows a plan view of the embodiment of FIG. 1;

FIGS. 6A and 6B show a perspective view and a diagrammatic view inelevation respectively of flexible moving means for the embodiment ofFIG. 1;

FIG. 7 shows cross section in elevation of a second embodiment of thelighting assembly according to the present invention;

FIG. 8 shows a schematic cross section in elevation of a thirdembodiment of a lighting assembly according to the present invention;

FIG. 9 shows a detail of the embodiment of FIG. 8;

FIG. 10 shows a plan view of an alternative carriage and moving meanswhich may be used in the duct shown in FIGS. 1, 5 and 7;

FIGS. 11A and 11B shows side views of the carriage of FIG. 10 indifferent positions in a generally sinusoidal duct as shown in FIGS. 1,5 and 7; and

FIGS. 12 and 13 which show prior art arrangements of lighting systemsfor hazardous areas.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to FIGS. 1 to 6 and where the same features are denoted bycommon reference numerals. A lighting assembly according to a firstembodiment of the present invention is indicated generally at 10 and isfixed within an aperture 12 of a wall 14 which has a first side 16 atthe side of a hazardous closed-off area 18 and a second side 20 sealedoff from the hazardous area 18 and accessible to operators. The lightingassembly comprises a container housing indicated generally at 22 andwhich is close fit inside a lining indicated generally at 24 inside thewall aperture 12. Seals 26 are provided between the lining 24 andhousing 22 to prevent any egress of contaminants from the first side 16to the second side 20. A duct 30 of non-linear shape is providedextending between the first side 16 and the second side 20; the ductbeing of a shape which prevents there being any direct shine path fromthe first side to the second side and also preventing any danger of γrays passing from the first to the second side by internal reflection.The duct 30 is fixed within the container housing 22 and surrounded byconcrete grout 32. At the end of the duct 30 adjacent the first side 16there is a volume 36 in which a reflector 38 is positioned, the volume36 being sealed off from the area 18 by a glass window panel 40 set inseals 42 in the container housing 22. The end of the housing 22 and theglass panel 40 are substantially flush with the wall face second side 16which is an advantage since there is no ledge formed on which hazardousdebris may settle should the housing 22 ever have to be removed from theaperture 12. The duct which is of rectangular cross section 44 is opento the volume 36 to allow access thereto of a light source 46 which isof elongate tubular cross section, in this case a high intensity sodiumlamp. The lamp 46 is mounted on power supply sockets 48 at the front endof a carrier trolley 50 (see FIGS. 4A and 4B) which comprises twoarticulated bogeys 52, 54 linked by pivoted 56 members 58 to each other(N.B. only the front bogey 52 is shown in FIG. 1); the bogeys 52, 54 areguided within the rectangular internal cavity 60 of the duct 30 byjockey wheels 62 running against the vertical walls 64 of the cavity 60and jockey wheels 66 running against the horizontal walls 68 of thecavity 60 thus positioning both the trolley 50 and lamp 46 within theduct. The lamp 46 is automatically located in its desired position byvertical flange faces 70 of the front bogey 52 meeting co-operatingfaces 72 of a plate 74 at the rear of the volume 36. To the rear face 76of the rear bogey 54 is fixed a flexible trolley moving member 80 shownin part only (see also FIGS. 6A and 6B) which comprises the type ofplastics material chain-track commonly used for grouping together andprotecting cables in conveyors and machine tools for example. Theconstruction of the flexible member 80 is shown in more detail in FIGS.6A and 6B and comprises hollow, generally box-shaped segments 82 pivotedto each other at 84 allowing flexibility in the vertical plane as seenin FIG. 1. The member 80 is constrained by the internal walls of theduct 30 and is able to apply a pushing and/or pulling force as requiredto the trolley 50 so as to position the lamp 46 in its desired position.The flexible member extends through the duct cavity 60 and when the lamp46 is in its desired position the remote end 88 of the duct 30 is sealedoff by a closure member 90 such that if the glass 40 should be broken ordamaged for any reason, no contaminants will emerge from the end 88 ofthe duct 30. The end 92 of the housing 22 is closed off and sealed by asecond closure 94 having an access door 96 sealable thereto and whichcontains the electrical power supply, indicated only by dashed lines 98,to the lamp 46, the power cables being routed through the hollowbox-shaped segments 82.

In operation to place or remove the lamp 46 it is only necessary toinsert the flexible member 80 in the duct 30 and push it home and closeoff the end 88 with the closure 90; the articulated trolley 50 guidingthe lamp 46 to its desired position. Thus, replacement of the lamp 46 isa matter of minutes rather than the cumbersome procedure of manyman-hours of prior art systems.

FIG. 7 shows a second embodiment indicated generally at 100 of alighting assembly of the present invention. In essence this embodimentis similar to that of 10, however, in this case there is a projection102 allowing a more downwardly lighting direction for illuminatingobjects in the area 18. As before, there is a container housing 22closely fitting a liner 24 fixed within an aperture 12 in the wall 14.In this embodiment the duct 30 is provided with inturned flanges 106 atits end adjacent the first side 16 to act as location means against thelamp holder 48 so allowing the lamp to be in its desired positionrelative to the reflector 38. All other features of this secondembodiment are similar to those of embodiment 10.

FIGS. 8 and 9 show a third embodiment indicated generally at 120 of alighting assembly according to the present invention. This embodimentcomprises an outer container housing 122 fixed in a wall 124 having afirst side 126 and a second side 128. The housing 122 contains aplurality of ducts 130 which are twisted together into the form of ahelix. As with previous embodiments, there is no direct shine path fromthe first side 126 to the second side 128. Each duct 130 is of circularcross section and receives a light source 132 in form of a halogen bulbin a holder assembly 134 which also constitutes the carrier means. Theholder assembly comprises a bulb holder 140 per se and a shroud andreflector assembly 142 which is adapted to slide within the duct tube130. The rear end 144 of the shroud 142 is fixed to moving means 146which is in the form of a flexible conduit having power supply cables148 passing therethrough. The bulb 132 and carrier assembly 134 islocated in position adjacent the first side by the forward rim 150 ofthe shroud 142 abutting against a glass window 152 at the first side. Atthe end 156 at the second side, there are, as before, a suitable powersupply and sealable doors (not shown) to isolate the first side from thesecond side. Although not shown in FIGS. 8 and 9, the assembly may alsoinclude a liner to the wall aperture 160 within which the housing 122may be fitted. Similarly, the free space within the housing 122 may befilled with concrete grout 160. Various sealing arrangements which arewithin the capability of a person skilled in the mechanical engineeringart may be devised and fitted so obviating any possibility of leakagepaths for contaminants from the first side to the second side.

FIGS. 10 and 11A and 11B shown an alternative form of carriage 200 andmoving means 202 which, although shown only in part, extends through theentire length of the duct 30 of FIG. 1 when the lamp 46 is in positionat the first side. The carriage 200 comprises a frame 204 of fabricatedsheet metal; the frame having jockey wheels 206 running on thehorizontal surface of the duct 30. Pivoted to the frame 204 at the frontaxle of the jockey wheels 206 is a lamp carrier member 208 including alamp socket 210 and an independent jockey wheel 212. Thus, the lamp 46is supported away from the duct floor and is able to follow thegenerally sinusoidal duct shape (indicated by the dashed line 216) ineither an upwardly 220 or a downwardly 222 direction as indicated inFIGS. 11A and 11B respectively. The rear of the frame 204 has aflexible, flat push/pull strip 202 of metal or plastics materialattached thereto which is sufficiently flexible to allow the carriage200 to be pushed home through the duct 30.

What is claimed is:
 1. A lighting assembly which extends through thethickness of a wall having a first side and a second side, the assemblycomprising: a container housing extending through an aperture in saidwall from the first side to the second side of the wall; at least onelight source to illuminate an area on the first side of said wall; andmeans being included within the container housing to enable replacementof said light source from the second side of said wall wherein saidmeans includes: at least one fixed duct extending at least part of theway from the first side of the wall to the second side of the wallwithin the container housing; light source carrier means on which saidlight source is mounted, said light source carrier means and said lightsource being movable through said at least one duct from said secondside to said first side and from said first side to said second side;moving means to move said light source and said carrier means throughsaid at least one duct; and power supply means to said light source; thelighting assembly being characterized in that a shape of the fixed ductis non-linear; in that said moving means are flexible and in that in usea failed light source is removed from the duct adjacent the second sideof the wall by retraction of the moving means.
 2. A lighting assemblyaccording to claim 1 wherein the shape of said non-linear duct isselected from the group consisting of generally sinusoidal and helical.3. A lighting assembly according to claim 1 further comprising locationmeans at the first side to locate the light source in a desiredposition.
 4. A lighting assembly according to claim 1 wherein an end ofthe container housing adjacent the first side of the wall includesreflector means.
 5. A lighting assembly according to claim 1 wherein avolume of the container housing about the duct is filled with grout. 6.A lighting assembly according to claim 1 wherein the duct has arectangular cross section.
 7. A lighting assembly according to claim 1wherein the duct has a substantially circular cross section.
 8. Alighting assembly according to claim 7 wherein there are a plurality ofducts in the assembly.
 9. A lighting assembly according to claim 1wherein the carrier means comprises one of a trolley and a bogey onwhich the light source is mounted.
 10. A lighting assembly according toclaim 9 wherein the trolley has means to maintain the trolley in adesired spatial orientation and position within the duct.
 11. A lightingassembly according to claim 10 wherein said means to maintain thetrolley comprises jockey wheels running on at least one of internalhorizontal and vertical surfaces of the duct.
 12. A lighting assemblyaccording to claim 1 wherein the flexible moving means comprises achain-track conveyor having segments in linear array and pivoted to eachother.
 13. A lighting assembly according to claim 1 wherein the flexiblemoving means comprises a flexible conduit able to adapt to the curvatureof the duct.
 14. A lighting assembly according to claim 1 wherein themoving means comprises a flexible, flat strip.
 15. A lighting assemblyaccording to claim 1 wherein the moving means comprises rotatable pulleywheels in fixed positions at least adjacent the first and second sidesof the duct and having an endless cable therearound and the carriermeans in the endless cable loop.
 16. A lighting assembly according toclaim 1 wherein a duct orifice at the second side is provided with aclosure having a seal therearound.
 17. A lighting assembly according toclaim 1 further including a fluid coolant supply to enable cooling ofthe light source.